Process for firing ceramic articles



Jan. 20, 1953 ca. M. .1. CREMER PROCESS FOR FIRING CERAMIC ARTICLES Filed Sept. 24, 1949 INVENTOR. Gaff/fled M. J. Cremer' I BY QZMW 0. F2

ZOEIUWW IO-l ZOFPUUW UZJOOU PUNK-D NZON UZZKUINEQ m-ZON 021-000 A rromvsy Patented Jan. 20, 1953 PROCESS FOR FIRING CERAMIC ARTICLES Gottfried Marius Josef Cremer, Frechen, near Cologne, Germany Application September'24, 1949, Serial No. 117,693

In Great Britain July 7, 1949 3 Claims.

This invention relates to a process for operatingdirec'tlyheated tunnel kilns for firing ceramic products and an object is to produce a new and improved process of this character by which the goods to be burned are advanced through the kiln in a quiescent atmosphere.-

Another object is to produce a process of the above character by which translatory seals are recurrently established in certain zones of the kiln as the goods to be burned progress through the kiln.

A further object is to produce a process of the above character by which a translatory seal is recurrently established at the inlet end of the kiln and removed after passage through a predetermined portion of the preheating zone,- and a similar seal is recurrently established during travel of the goods through a predetermined portion of the cooling zone and subsequently removed after completion of such travel. 7

Other objects and advantages will hereafter appear, and for purposes of illustration but not of limitation, an embodiment of the invention is shown on the accompanying drawing, in which the figure is a diagrammatic view partly in section of an open-ended tunnel kiln.

The illustrated embodiment of the invention comprises a directly heated tunnel kiln 2', which is open at opposite ends and extending through the kiln is a track 3 on which an uninterrupted series of wheeled firing cars 4 are driven in a sub stantially continuous manner by, a conventional pressure fluid operated linear motor 5 embodying a horizontal operating piston working in a cylinder. The tunnel kiln consists oi a plurality of zones which are sequentially arranged from the inlet end as followsz apreheating zone having a smoke section 6 anda preheating section a firing zone 8; and a cooling zone having an in direct cooling section 9 and a direct cooling section 18.

Details of the heating and cooling of the kiln form no part of the present invention and accordingly, detail description and illustration thereof are not considered necessary. Suiiice it to say that the smoke section 6 may be directly heated by hot air introduced under pressure from the preheating zone and this coupled with the seal effected between the smoke section and preheating section by the slides I l and cooperating packing, the atmosphere in the connecting zones remains quiescent. The zones in which the material is particularly sensitive are the preheating zone and the part of the cooling zone in which the material is cooled down to the critical point in 2 which recrystallization from B quartz to a quartz takes place, that is, from 575 C., while in the other zones in the kiln the material is comparatively insensitive.

Intermediate the smoke section 6 and preheating section I is a vertical slot H in a side wall of the kiln. A similar slot i2 is provided in a side wall in the region between the indirect cooling section 9 and the direct cooling section I0. Finally, another similar slot i3 is in a side wall approximately midway of the direct cooling section It. Preferably, the slot H is spaced at a distance of at least four carriage lengths from the inlet end of the kiln, and the slots I2' and I3 are spaced from each other at least three carriage lengths.

Recurrently mounted on certain of the firing cars is a vertically disposed slide M which consists of a metal plate conforming to the shape of the firing conduit of the kiln. Each plate or slide M has a flexible packing [5 in the form of a metal brush to bear against the wall and arch of the conduit thereby forming a labyrinth seal which for given pressures and gas velocities afford a sufficient seal.

The slides M are 'mounted at their lower ends between two cars and are suitably supported on the car platform on which they stand securely without in any way disturbing the firing stock on the car because they are arranged on that portion of the car which could not receive the stock.

For assisting in the prevention of axial flow of air through the firing conduit, brush packing joints iii are arranged between the side walls of the conduit and the sides of the cars. These packing joints are preferably arranged in the sidewalls of the firing conduit: for .a distance equal at. least in the length of a car in front of the slots II and It. The brushes l6 are provided in both side walls of the firing conduit opposite to each other and in conjunction with the slides It effect a sealing of one zone from the others or from the outside. Any disturbance of the properly produced conditions in the individual sections by the inlet of undesired air is as a practical matter, eliminated.

The linear motor or car advancing device 5 is so adjusted that upon completion of its forward stroke, the slides is will have reached the withdrawal slots II and I3 respectively and are removed from the cars during the retracting movement of the linear motor. For withdrawing the slides, gripping jaw devices I! engage the top portions thereof and these devices are ambulatory on tracks l8 respectively which extend rearwardly to the entrance slot [2 in the one instance, and to a point externally of the kiln at the inlet end in the other instance. Thus the slides are conveyed back for mounting on succeeding cars and the above operation is repeated at intervals as will be readily understood. The above operation takes place rapidly so that only short pauses are necessary which as apractical matter, do not interrupt the continuous operation of the kiln.

From the above, it will be apparent that according to this process the products to be burned are arranged on cars 4 in an unbroken sequence passing in a practically continuous manner through the successively arranged zones of a directly heated open-ended kiln. A seal is established by a slide at the inlet end of the kiln, such seal traveling with the goods on the cars until it reaches the end of the smoke section 6 where the slide is removed and at the same time a seal is established by means of a slide at the inlet end. Similarly, a seal is established at the beginning of the direct cooling section 9 and removed subsequently whereupon another seal is established at the beginning of the direct cooling section in a recurrent manner. The train or sequence of groups of goods to be burned is advanced in a substantially continuous manner, the seals being recurrently established and removed during the retracting movement of the linear motor 5. Although the various zones are not sealed against each other, they are sealed against the outside atmosphere thereby increasing the efficiency of the kiln.

Having now particularly described and ascer' tained the nature of my said invention and in what manner the same is to be performed, I de clare, that what I claim is:

1. A process for firing ceramic products in an open ended directly heated tunnel kiln having successively arranged preheating, burning and cooling zones which consists in substantially continously advancing groups of products to be burned arranged in close uninterrupted sequence, recurrently establishing a translatory seal at the inlet end of the kiln to travel along with the associated groups, removing the seal after passage thereof through a predetermined portion of the preheating zone, similarly and recurrently establishing a translatory seal to travel with the associated groups through a predetermined portion of the cooling zone, and removing the latter seal after passage thereof through such predetermined portion.

2. A process for firing ceramic products in a directly heated tunnel kiln open from end to end and having successively arranged preheating zones including a smoke and preheating sections, a burning zone, and a cooling zone including directly and indirectly cooling sections, which consists in advancing groups of products to be burned arranged in close uninterrupted sequence, recurrently establishing a translatory seal at the inlet of the kiln to travel along with the associated groups, removing the seal after passage thereof through the smoke section of the preheated zone, similarly and recurrently establishing a translator-y seal to travel with the associated groups through the direct cooling section of the cooling zone, and removing the latter seal after passage thereof through such direct cooling section, the advancing movement being continuous except for momentary pauses for establishing and removing the translatory seals.

3. A process for firing ceramic products in 2. directly heated tunnel kiln open from end to end and having successively arranged preheating zones including a smoke and preheating sections, a burning zone, and a cooling zone including directly and indirectly cooling sections, which consists in step by step advancing groups of products to be burned arranged in close uninterrupted sequence, recurrently establishing a translatory seal at the inlet of the kiln to travel along with the associated groups, removing the seal after passage thereof through the smoke section of the preheated zone, similarly and recurrently establishing a translatory seal to travel with the associated groups through the direct cooling section of the cooling zone, and removing the latter seal after passage thereof through such direct cooling section, the advancing movement being substantially continuous except for momentary pauses during which the respective seals are established and removed.

GOTTFRIED MARIUS JOSEF CREME.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 75,096 Whittemore Mar. 3, 1868 120,965 Hall Nov. 14, 1871 1,075,904 Drayton Oct. 14, 1913 1,321,388 Owens Nov. 11, 1919 1,384,435 Dressler July 12, 1921 1,610,968 Robertson Dec. 14, 1926 1,628,273 Richardson May 10, 1927 1,693,152 Meehan Nov. 27, 1928 1,705,477 Hanley, Jr Mar. 19, 1929 1,814,906 Duckham July 14, 1931 1,862,548 Prouty et al June 14, 1932 2,207,412 Prouty July 9, 1940 2,218,935 Ingersoll Oct. 22, 1940 2,418,650 Mackey -1 Apr. 8, 1947 2,474,301 Blaha June 28, 1949 

